1. Field
The technological field relates to a battery pack and a method of sensing a voltage of the battery pack.
2. Description of the Related Technology
In general, a battery pack includes a plurality of battery cells, a cell voltage sensing unit configured to sense voltages of the battery cells, and a control unit configured to use information obtained from the cell voltage sensing unit to prevent overcharge or overdischarge of the battery cells and to calculate capacity of the battery cells.
The cell voltage sensing unit is typically formed as a single integrated circuit (i.e., a single semiconductor chip), and designed to sense voltages of 1 to 4 battery cells that are connected in series. Also, the control unit is formed as a single integrated circuit (i.e., a single semiconductor chip), and is designed to communicate with the cell voltage sensing unit. The cell voltage sensing unit is typically referred to as an analog front end, and the control unit is typically referred to as a micro processing unit.
The maximum number of battery cells permitted by the single cell voltage sensing unit ranges from 1 to 4. However, in recent years, a battery pack provided with 5 or more battery cells connected in series is required. For example, a battery pack installed on electric tools for high capacity and large power requires 5 to 6 battery cells connected in series. Thus, to permit 5 battery cells, an additional expensive cell voltage sensing unit should be provided, or an additional complicated circuit should be designed since the maximum number of battery cells permitted by a single cell voltage sensing unit is just four as described above.